High voltage circuit breaker having a switch rod made of an insulating material

ABSTRACT

In a high-voltage circuit breaker having an interrupter unit that can be actuated mechanically and that can be driven by a switch rod made of an insulating material, it is provided that the switch rod has at least two segments that are pushed into one another in partially overlapping telescoping fashion and that are connected with one another, the region in which the segments overlap one another and/or the segment having the larger outer diameter being arranged in the region of the greatest mechanical loading of the switch rod.

FIELD OF THE INVENTION

The present invention relates to a high-voltage circuit breaker havingan interrupter unit that can be actuated mechanically, a switchmechanism and a switch rod that is made of an insulating material, thattransmits a drive motion, and that is at least partially hollow.

BACKGROUND INFORMATION

A high-voltage circuit breaker of this type is described in for example,German Utility Model No. G 92 12 434 8 . This reference, describes atension or pressure rod made of fiber-reinforced insulating material fordriving a switch of this type. There the switch rod is made of onepiece, connected at its ends with metallic armatures via a gluedconnection.

In a high-voltage circuit breaker of this sort, there is the problemthat for the switching process, very large powers have to be transmittedvia the switch rod, so that correspondingly large forces must betransmitted, both as tensile forces and also as pressure forces. In thiscontext, the greatest problems result in the transmission of a pressuremotion. If a boundary force that follows from the Euler bucklingequation is exceeded, a switch rod can buckle and can be destroyed.Here, according to the theory that the buckling equation fundamentallyapplies, a sinusoidal oscillation of the switch rod is to be assumed;this rod then buckles in the region of one or several oscillation loopswhen the boundary force is exceeded.

Conventionally, such a buckling is normally countered by sufficientdimensioning of a switch rod of this sort, or by lateral guides thatprevent the buckling through the application of a counterforce.

SUMMARY

An object of the present invention is to provide, in a high-voltagecircuit breaker, an economical switch rod that nonetheless operatesreliably and in particular is also light, in order to keep the massesthat are to be accelerated in the switching process low.

This object is achieved in that the switch rod has at least two segmentsthat are pushed into one another in partially overlapping telescopingfashion and are connected with one another, the region in which thesegments overlap one another and/or the segment having the larger outerdiameter being arranged in the region of the greatest mechanical loadingof the switch rod.

According to the present invention, the switch rod is thus assembledfrom a plurality of segments, such that for example the end segments arenot required to receive any particularly large lateral, that is radial,loads. In contrast, the middle region of the switch rod is exposed togreater radial loads, thus, the possibility of buckling is feared. Theswitch rod can be assembled such that a segment having a larger outerdiameter is arranged in this middle region, segment having a higherbuckling stability than the regions having a smaller outer diameter.However, it can also be provided that two segments overlap precisely inthe middle region of the switch rod, so that the required bucklingstability is achieved through the overlapping in this region.

An advantageous construction of the present invention provides that thesegments are glued to one another.

By gluing, the rod segments are connected with one another in aconstructively simple and reliable fashion.

It can also advantageously be provided that the segments are screwedtogether.

This type of fastening enables problem-free disassembly of a switch rod.

In addition, it can advantageously be provided that the segments areshrink-fitted to one another.

In this case, it is not necessary to take into account the durability,or material consistency with a rod material, of an adhesive.

Another advantageous construction of the present invention provides thatrod segments having an enlarged outer diameter are arranged at thepoints at which there is a danger of a buckling in the case of alongitudinal compression of the switch rod, in particular according tothe Euler buckling equation.

In addition, it can advantageously be provided that the switch rod ismade up of three segments, of which the middle segment has an innerdiameter that corresponds approximately to the outer diameter of theother two segments, the middle segment forming the middle region of theswitch rod.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows the design of a high-voltage circuit breaker.

FIG. 2 schematically shows the composition of an inventive switch rod.

DETAILED DESCRIPTION

A high-voltage circuit breaker has a pole column 1, 4, made up amongother things of a support 4 and a housing 1 for an interrupter unit 2.Both support 4 and housing 1 can be made either of porcelain or of acompound insulating material.

The electrical terminals for the high-voltage circuit breaker arelocated on one hand at the upper end 13 of interrupter unit 2, and onthe other hand at the lower end of housing 1, in the region of metalflange 5.

Support 4 and a part of housing 1 are penetrated by a switch rod 6 thatcan be moved in the axial direction by a switch mechanism 7 both upwardsin the direction of arrow 3 and also downwards. For this purpose, switchrod 6 is provided with armatures at its ends, a crank 9 being providedat the lower end; this crank can be actuated by a drive rod 8, which forits part can be driven by switch mechanism 7.

Switch mechanism 7 can be either a hydraulic drive or a spring-loadeddrive.

Interrupter unit 2 has two contacts that can be driven against oneanother, of which for example the lower one is connected with switch rod6.

In order to achieve a rapid breaking or closing of a contact, highaccelerations of the movable contact and of switch rod 6 are necessary,and as a result large forces to be transmitted in the axial direction ofswitch rod 6 are necessary.

In particular given a pushing motion of switch rod 6 in the direction ofarrow 3, switch rod 6 can buckle laterally if it is not correspondinglystabilized.

In FIG. 2, switch rod 6, made up of three segments 10,11, 12, is shownin the horizontal position. Middle segment 11 of switch rod 6 has aninner diameter that corresponds approximately to the outer diameter ofouter segments 10, 12 in overlapping region 14, so that for exampleouter segment 12 can be pushed into middle segment 11 with a small gap.This gap can for example be filled with an adhesive, or an innerthreading can be attached to middle segment 11 and an outer threadingcan be attached to outer segment 12, so that these segments can bescrewed to one another.

It is also Possible to provide volts or screws that radially penetratethe two segments 11, 12 in overlap region 14, thus connecting thesesegments with one another.

Depicted switch rod 6 has in its middle region, where it is formed bymiddle segment 11, a significantly higher buckling stability than inouter segments 10, 12. In outer segments 10, 12, it is not loaded sostrongly towards buckling as in middle segment 11. However, through thedepicted construction, switch rod 6 is provided with a reduced outerdiameter and a correspondingly reduced inner diameter in comparison tomiddle segment 11 in the region of outer segments 10, 12, so that theswitch rod has a correspondingly lower mass in the outer regions, andhas a lower mass overall than a correspondingly stable continuous switchrod.

In this way, the mass to be accelerated in case of switching is reducedas a whole, thus enabling a savings of drive energy.

Switch rod 6 is also particularly stable in the regions of overlappings14, 15.

What is claimed is:
 1. A high-voltage circuit breaker, comprising: amechanically actuated interrupter unit; a switch mechanism; a switch rodmade of an insulating material and being at least partially hollow, theswitch rod being associated with the interrupter unit and the switchmechanism, the switch rod being configured to transmit a drive motion inan axial direction, the switch rod including at least two segments thatare pushed into one another in a partially overlapping telescopingfashion, the at least two segments being connected to one another, atleast one of: i) a region in which the at least two segments overlap oneanother being arranged in a region where the switch rod tends to buckleas the result of a mechanical loading, and ii) a first one of the atleast two segments having a larger diameter being arranged in the regionwhere the switch rod tends to buckle as the result of the mechanicalloading.
 2. The high-voltage circuit breaker according to claim 1,wherein the at least two segments are glued to one another.
 3. Thehigh-voltage circuit breaker according to claim 1, wherein the at leasttwo segments are screwed to one another.
 4. The high-voltage circuitbreaker according to claim 1, wherein the at least two segments areshrink-fitted to one another.
 5. The high-voltage circuit breakeraccording to claim 1, wherein the region where the switch rod tends tobuckle is at a point at which there is a danger of a buckling during alongitudinal compression of the switch rod.
 6. The high-voltage circuitbreaker according to claim 5, wherein the region where the switch rodtends to buckle is a location determined according to a Euler bucklingequation.
 7. The high-voltage circuit breaker according to claim 1,wherein the at least two segments includes three segments, a middle oneof the three segments having an inner diameter that corresponds to anouter diameter of another two of the three segments, the middle segmentforming a middle region of the switch rod.